Electric fuel pump designs have evolved to a steady design state of employing gerotors, roller vanes, or modified fluid turbine principles for generating high fuel pressure in essentially all current vehicle applications. Fuel is picked-up by such fuel pumps over an arc extending between 60.degree. and 120.degree. around a pumping channel formed along the pumping element circumference. Low pressure and high pressure regions are thus created at the fuel inlet and fuel outlet, respectively, which are at opposite ends of the channel. Since the pumping channel terminates abruptly at the outlet, a pulsing effect is created as the pumping element rotates past the non-channel circumferential portion of the pump housing. These hydraulic pulsations result in decreased pump efficiency since high energy fuel either is carried from the high pressure side to the low pressure side or leaks across. In addition, prior fuel pump inlets have a sudden pressure decrease in the vacuum stage leading to the pumping channel inlet thus creating turbulence and enhancing the conditions which promote undesirable cavitation. These prior inlets also had a secondary backflow which reduced pump efficiency.
Other pumps, such as that disclosed in U.S. Pat. No. 4,880,352 (Aarestad), have side inlets, as opposed to the end inlet of the present invention, which do not ramp fuel into the impeller inlet channel. In addition, the pump shown in the Aarestad patent picks up fuel through only 180.degree. as opposed to at least 340.degree. for the present invention.